It turns out that while Mac OS 9 does in fact come with version 1.3.5 of the USB drivers, it doesn’t support PC Card USB adapters such as the MacAlly CardBus-to-USB card because, according to an Archive PowerPage reader, ‘it does not install the “USB Support” extension found in the Adapter Card DDK.’ The DDK is Apple‘s driver development kit, so be warned that it’s intended for developers. This reader has also successfully tried the USB PC card ‘with a Stylus Photo 750, and iMac mouse, and a third party ergonomic keyboard. The card supports hot swaps and waking from sleep seamlessly.’

The DDK includes complete installation instructions in the package. One of the steps involves the use of ResEdit, sort of as a litmus test to see if you’re really a developer, so if you don’t know how to use ResEdit, it may be best to leave it alone.